Automatic switch



L. SCHUN.

AUTOMATIC swncn.

APPLICATION FILED APR. 20, 1912- 1,405,338, Patented Jan. 31, 1922.

UNITED STATES PATENT OFFICE.

Lonwmscnoir, or nssEN-oN-TnE-RUnB, GERMANY, ASSIGNOR T FRIED. more AKTIENGESELLSCHAFT, or nssmv-on-rnn-nunn, GERMANY.

AUTOMATIC swrron.

Specification of Letters Patent.

atented Jan. 31 1922.

i Application filed April 20, 1912. Serial No. 692,120.

. (GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. In, 1313.) v

To all whom it may concern:

Be it known that I, L nwIo SoHoN, re-

siding at Essen-on-the-Ruhr, Germany, a

subject of the Emperor of Germany, have invented a certain new and useful Improvement in Automatic Switches, of which the following is a specification.

The present invention relates to such automatic switches for alternatelyopening and closing an electric circuit, which are provided with a device for changing the ratio between the duration of the closing and opening. The object of the invention is to provide a switch of this kind and of very simple construction, wherein not only this ratio can be changed within wide. limits, and in a; steady and very. accurate manner, but also the arising ofinjurious break sparks is excluded.

The accompanying drawing shows in- Fig. 1 aside view, partly'in section of one embodiment of this invention with a dia:

, grammatic representation of aconnection for a dynamo, wherein the tension in known manner is regulatedby changing the relation of duration of the closing and open- Fig. 2, a section along line 22 of Fig 1, seenfrom the left; g f

Fig. 3, a diagrammatic sketch corresponding to Fig. 2 illustratingfthe manner of operation of the device in accordance with Figs. 1 and 2.

The field winding A of the dynamo B is connected to the two main lines +S and S of a network of continuous current by means of conductors C and C The device constituting the present invention for changing the opening and closing of the electric circuit, is inserted in conductor G. This device consists principally of acylindrical rotor D, which is rigidly mounted on a shaft H, running in bearings Gr, G G and of two sliding brushes E, E resting on the rotor D, which brushes E and E see Fig. 1, are displaced axially relative to each other. One of these brushes E, is rigidly connected to the bearing G by means of an arm 9 whilst the other brush E is seated on a revoluble arm g arranged on the bearing G; so that the latter brush may be set at any desirable angle relative to the brush E. That part oi: the jacket of the rotor D which consists of non-conducting material is provided around its whole circumference wlth lamellae 03 some on the rotor D by any suitable means such as screws or the like. Thetwo brushes E and E? are to be dimensioned in the circumferential direction so that each brush in every angular position of the rotor D touches at least one of the 'lamella. An electricmotor F serves to drive the rotor D. The rotor F of the former is carried by the shaft H.

For the sake of simplicity it will be supposed that the brushes E and IE only touch the rotor D with a thin edge, see Fig. 3, which illustrates the operation of the described device; and the lamellae 05 shortcircuited by themember d are substituted by a single contact piece 45, the central angle a of which is equal to the central angle of the member d". This supposition is admissible, because, as is mentioned above each brush always touches at least one 0% the lamellee, and "the short-circuited lamellae may be considered "as a single contact piece as regards the contact with the brushes. Should the adjustable brush E be set in the positionindicated by dot and dash lines, wherein it is turned as regards the brush E an angle the circuit can then be closed only during that instant that corresponds to the turning angle acp, which is easily understood from Fig. 3, as by the end of this time the brush E will be out of reach of the sliding contact d. The i value assume its maximal value for an angular distance of qz a and will for, an angular distance of e:(). It will also be evident, that within these limits the ratio of the displacement of the brush'E can be changed in a steady and Very accurate manner. V @I i If the contact between the brushes E and E} and therotor D does not take place, as

has been supposed in Fig. 3,. with; 'a' thin edge, but instead with a broad, surface, see Fig.2, which in reality is the case, the van-V gle corresponding to the central angle lot the contact surfaceof the brushes must be considered enlarged, in order that the last derived equation shall hold good. In the samewvayas above described'for the case of a single contact piece, the device shown in Figs, landQ works in the case of a rotor withf'lamellae d ,"some ofwhich are short-circuited by the member (Z As the lamellae which are not connected by means ofthe short circuit member (Z? can never produce" a connection between the two brushes as long as the angular displacement between the brushes E and E (see Fig.2)

is no't equal to or almostlequal to zero,1the opening and closing ofjthe circuit will. evidently follow in the. same length of time,

as in the arrangement according to Figl 3,

35. With the exception of when the brushes have a angular 'displacementiof vzero as just mentioned.

The construction of the rotor in the shape of, a collector providesthe advantage, that the sparks at the break are sooner 'eXtin-. g'uished by jumping over to the nearest lamellae, than what is' the casein known devices. The circumferential adjustability of the short circuit member "d makes it possible to proportionately divide the resultingwearall over the lamellae of the rotortD notwithstanding the influence of the sparks. r

Claims.

1. In an automatic switch opening andclosing an electric circuit, a device for changing the ratio betweenthe for alternately duration of the closing and opening, como prising a rotor, two. brushes "resting on said rotor, one of said brushes being circuniferentially adjustable regards the other brush, 'forl'the purpose of changing the ratio between the duration-of the closing and opening g N I as a laminated collector, and having a short said rotorbeing' constructed circuit :memb'er connecting some "of the lamellee of said'rotor. l p

2.111 an automatic switch for alternately opening and closing an electric circuit, a deviceior changing theyratio between the duration of theclosingand opening, comprising a rotor, two brushes resting on said rotor,' one of said brushes being circum-Z ferentially adj ust able'as regards ;-the 1 other brush, for the purpose of changing theratio between the duration of the closing and opening, said rotor being constr'u'ctedfas a laminated collector, and havinga short circuit -inember, connecting some of "the 

